1. Field of the Invention
The present invention relates to a spring clamp system. More specifically, the present invention relates to a spring clamp system which provides for rapidly interchangeable clamps and adjustable interlock positioning.
2. Description of the Related Art
Spring clamps are conventionally used for applying clamping forces to workpieces in opposing directions. Spring clamps include a pair of lever arms each with handles and opposing gripping jaws adapted to open and close on a work piece interposed there between. Light-duty spring clamps, sometimes called “squeeze clamps,” can be quickly and conveniently applied to workpieces because they require no adjustment and are relatively inexpensive.
The gripping jaws of conventional spring clamps have a pair of work engaging surfaces. In some types of conventional spring clamps these work engaging surfaces are capable of universal alignment with a workpiece. The work engaging surfaces are most frequently affixed to the gripping jaws in a manner allowing motion about one coordinate plane. Consequently, in operation the work engaging surfaces of conventional spring clamps can close upon workpieces in a variety of non-parallel modes and hold and retain workpieces having unusual configurations.
Respective lever arms are joined at a central point where a torsional spring member provides an urging closing force between the opposing gripping jaws thereby enabling constant pressuring during a clamping operation, such as, for example, gluing, nailing, or the like. Examples of this type of conventional spring clamp can be found in U.S. Registration Nos. 5,765,820 and D350,891.
Conventional spring clamps provide a limited range of uses relative to a work piece. During use, opposing gripping jaws are placed in an opened position in which the are spaced apart and positioned over a workpiece to-be-clamped. After positioning, the levers are released and the torsion spring member urges the gripping jaws into a closed position in which the opposing gripping jaws are spaced together with the workpiece secured there between.
Alternative conventional spring clamps include a non-removable pin fixably extending from one of the opposing handles opposite the gripping jaw. The fixed pin joins the conventional spring clamp to a friction-connective member having a fixing clasp. During use, this type of conventional spring clamp is, for example, attached to a desk edge and a piece of note paper is fixed in the fixing clasp. In this manner, a conventional spring clamp can be used as a light-weight note holder. An example of this type of conventional spring clamp can be found in U.S. Registration No. D420,896.
During use, the physiological action of closing a human hand around the lever arms of a conventional spring clamp results in opposing lateral vectors applied to each handle relative to a clamping plane. During opening, these opposing lateral vectors combine and create a lateral torsion relative to a clamping plane causing undesirable handle-to-handle misalignment and transverse handle bending at high clamping pressures.
The handles on each lever arm are conventionally constructed from a semi-rigid material, such as metal or plastic, and rolled or formed into a broad U-shape to resist lateral torsional bending during use. Where demand for increased closing force exists, conventional spring clamps increase the weight of the torsional spring member, resulting in a corresponding increase in opening pressure expressed on the handles of the lever arms perpendicular to the clamping plane. This results in an increased risk of bending and misaligning the handles despite the U-shape.
Conventional cures to this increased bending risk include thickening the semi-rigid handle material, resulting in increased cost, and extending the walls of the U-shaped handles resulting in thicker handles, difficulty for small-handed users, and a corresponding reduction in clamping capacity. Where these conventional cures are insufficient, the handles are misaligned, cannot close properly, and break easily.